"The range of facial expressions is as infinite as the range of human experience." --Anon.
The face is said to mirror the mind, and with rare exceptions such as expert poker players and catatonics, a person's facial expression provides a wealth of information regarding that person's emotional state and mental processes. One need only witness the response of a parent to his or her infant's smile to realize that facial expressions form a key element of human interaction throughout a person's entire life. The infant gains an increased sense of self-awareness as he emulates other people's facial expressions and notes the responses.
In recognition of the fact that facial expressions remain a fascinating part of a child's experience, there have been developed a number of children's toys based on the ability to construct a variety of facial expressions. For example, U.S. Pat. Nos. 1,525,103 and 156,338 disclose rectangular blocks having various facial features imprinted on their surfaces so that a user, by juxtaposing blocks having indicia corresponding to particular features, can construct a wide variety of faces. The interest in faces is not restricted to young children, and U.S. Pat. No. 3,879,861 which shows a character analysis educational game wherein a wide variety of faces may be built up from a stock of noses, mouths, chins, etc. This modular concept of facial construction also forms the basis of the police artist identification kit and the child's "potato head" games.
With respect to these various toys, placement of the movable elements is generally dictated by the unambiguous nature of the facial portion represented on the block or playing piece. By providing enough variations on each facial feature being depicted, a rather large variety of possible human faces may be formed. However, the parts tend to fit together in an unambiguous fashion. Thus, when a user tires of rearranging the same kind of pieces in the same kind of ways, albeit to get a variety of faces, the game or toy has lost its appeal. The key to a toy's long term success is its ability to maintain the interest of the user as the user gains more experience with the toy. This in effect presents a dual requirement since unless a beginner can quickly master the basic rudiments of the toy's operation, he is likely to become discouraged and abandon efforts to improve his level of skill. In such a case, the toy can scarcely be said to have universal appeal. Conversely, a toy that is capable of a limited number of arrangements, or perhaps mere variations on a single theme, fails to hold the interest of the user for more than a short period of time.
Jigsaw puzzles are well known for providing users of all ages with gratification and challenge in the areas of geometrical and pictorial relationships. However, given that a jigsaw puzzle can only be assembled in one way, a given jigsaw puzzle is generally addressed to users at a particular level of skill. An alternate but related approach is to construct a puzzle whose pieces can fit together many ways, thus allowing young people to at least assemble the puzzle, while providing additional challenge and variety by having the pieces marked to produce designs of varying degrees of intricacy. U.S. Pat. Nos. 3,637,217 and 3,986,293 disclose puzzle block toys wherein certain areas may be filled in by different subsets of elements in order to form a wide variety of intricate geometric patterns. If such puzzle toys can be said to have a weakness, it is the fact that many people do not find geometrical designs particularly interesting, being "more interested in people than things."